Conventional fire hydrants offer access to a municipal water supply in a manner which operatives with ill intent may appreciate. Briefly, conventional fire hydrants include at least one nozzle for coupling to a fire hose. A threaded cap closes off the nozzle when the hydrant is not in use. The hydrant also includes a hydrant valve which controls flow of water from the water supply to and through the hydrant, through the nozzle, and into the fire hose.
Conventionally, the barrel of the hydrant between the nozzle and the hydrant valve, which is in the lower portion of the hydrant, accommodates several gallons of fluid. Accordingly, it is possible to unscrew a nozzle cap, introduce gallons of toxin, reattach the nozzle cap and open the hydrant valve to allow the toxins to communicate with and flow by gravity and perhaps at least to some extent by Bernoulli's principle, into the municipal water supply, since when the nozzle cap is attached, water pressure from the water supply would not force the toxins back out of the hydrant.
U.S. patent application U.S. Ser. No. 11/265,051, entitled “Fire Hydrant With Second Valve,” which is a continuation-in-part of U.S. patent application U.S. Ser. No. 10/309,646, entitled “Fire Hydrant With Second Valve,” the entire contents of each of which are hereby incorporated by this reference. Briefly, these documents disclose a seat affixed to the interior cavity of the fire hydrant using an adhesive or mechanical means, and another secondary valve structure introduced between the nozzle and the hydrant valve which cooperates with the seat to make it more difficult or impossible to introduce toxins to a water supply through a fire hydrant. The valve structure prevents or substantially prevents the flow of water through the valve and thus closes off portions of the hydrant barrel when a nozzle is open but the hydrant valve is closed. Generally, the valve structure comprises a secondary valve, a seat, and biasing structure.
Generally, when the hydrant is used to provide water to extinguish fires, or otherwise, a nut on top of the fire hydrant is rotated in one direction to open the primary and secondary valves inside the fire hydrant barrel. Water flows through the hydrant and out the nozzle. When the need for the water no longer exists, the nut is rotated in a second direction closing the primary and secondary valve.
Water may remain in the fire hydrant cavity after the primary and secondary valves are closed. Some conventional fire hydrants provide a drain or weep hole at the base of the hydrant to allow the water in the fire hydrant to drain to the exterior of the hydrant. Water must drain from the hydrant to prevent water, in colder climates from freezing and damaging the hydrant
Hydrants with a secondary valve not only prevent water and toxins from mixing, but also, in some instances, prevent atmospheric conditions from the hydrant barrel above the secondary valve to reach the area of the hydrant barrel below the secondary valve. Since air from the atmosphere does not reach the interior area of the hydrant below the secondary valve, the water may not, in some circumstances, drain or weep through the drain hole. Therefore, a need exists for a mechanism that allows water or other liquid to drain out the drain hole of a fire hydrant when the secondary valve is closed.